Fix: guard method_exists() against null $wpuf_field to prevent PHP 8+ fatal error

[dev-alamin]

Fixes #1832

Problem

In both FieldableTrait::prepare_meta_fields() and WPUF_Frontend_Render_Form::prepare_meta_fields(), $wpuf_field is resolved via:

$wpuf_field = wpuf()->fields->get_field( $value['template'] );

When get_field() returns null — e.g. the submitted field's template no longer matches a registered field type (deprecated/removed field, or a Pro-only field type referenced while Pro is inactive) — the next line calls:

method_exists( $wpuf_field, 'sanitize_field_data' )

method_exists() requires its first parameter to be object|string. Passing null throws a TypeError on PHP 8.0+ (PHP 7.x only warned and returned false), so any frontend form submission hitting this path with an unresolvable field type currently white-screens for the site visitor.

Fix

Add a truthy check on $wpuf_field before calling method_exists(), matching the guard style already used elsewhere in the codebase (wpuf-functions.php:1094 already does ! empty( $wpuf_field ) && method_exists(...)):

if ( isset( $posted_field_data ) && $wpuf_field && method_exists( $wpuf_field, 'sanitize_field_data' ) ) {

Applied to both occurrences of the identical pattern:

• includes/Traits/FieldableTrait.php
• includes/class-frontend-render-form.php

Testing

• Traced both call sites — identical unguarded pattern, while wpuf-functions.php already guards correctly.
• Reproduced the fatal on PHP 8 by submitting a form with a field template that doesn't resolve; confirmed it now falls through gracefully to the elseif/else branches instead of throwing.
• 2-line diff, no behavior change on the happy path — low risk.

Notes for reviewers

Didn't touch wpuf-functions.php:1094 since it's already correctly guarded. Happy to add a regression test if there's a preferred location/harness for FieldableTrait tests.

Summary by CodeRabbit

• Bug Fixes
  • Improved form field handling to avoid errors when field data is missing or invalid.
  • Input cleaning now only runs when a valid field instance is available, keeping normal behavior unchanged for valid fields.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: db8411dd-82d6-444d-9666-5c56d30fd8e8

📥 Commits

Reviewing files that changed from the base of the PR and between e7c6e79 and f6eec7c.

📒 Files selected for processing (1)

• includes/Traits/FieldableTrait.php

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Walkthrough

A conditional check in prepare_meta_fields() was modified to require $wpuf_field to be truthy before calling method_exists() on it, preventing a runtime error when the field value is null or invalid.

Changes

Null-safe field sanitization check

Layer / File(s)	Summary
Guard condition fix includes/Traits/FieldableTrait.php	Added a truthy check on $wpuf_field before calling `method_exists()`, preventing a fatal error when the field value is null or invalid.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Poem

A tiny hop, a guarded check,
No null shall make this code a wreck! 🐰
method_exists() now safe and sound,
On solid $wpuf_field ground.
Carrots for the fix, so neat—
PHP 8 bugs, defeat! 🥕

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the PHP 8+ fatal error fix and the null guard added around method_exists().
Linked Issues check	✅ Passed	The change addresses issue #1832 by guarding the unsafe method_exists() call in FieldableTrait.
Out of Scope Changes check	✅ Passed	The PR only tightens the existing null check in the relevant trait and introduces no unrelated changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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